Automatic stack type air filter



AgNuTTxNG UTQATIC STACK TYPE AIR FIIMTBR Filed April 4. A19348 2 sheets-sheet 1 Nov. s, 1940.

A. NUTTI'NG A AUTOMATIC STACK TYPE AIR FI-LTBR F11ed Apri1 4, 193s l mouwen o V V 2 Sheef-,s-Sheet 2 "uw W o bl @vl 'Gul o @Algra Patented Nov. 5, 1 940 UNITED STATES PATENT "o1-FICE AUTOMATIC sTAox FILTER Arthur Notting, `Louisville, Ky., assigner to American Air Filter Company, Inc., Louisville, Ky corporation of Delaware Application April 4, 1938, SerialNo. 199,848 11 claims. (cl. iss-9) This invention relates to air. iilters of the-charl v ing and replacing a illter'unit, to provide a novel stack supporting arrangement, and to provide a novel arrangement which permits one unit t soak while another unit is draining.

A further object of the invention is the provision of simple and dependable means for controlling and regulating the gravitational movement of the stack so 'as to lower it gradually and in proper timed relation.

The invention is illustrated in the accompanying drawings, wherein:

Fig'ure 1 is a side elevation view oi the lower 'portion of an air iilter` stack of the character f mentioned, with my improvements applied thereto, the filter casing being broken away; l

Figure 2 is a partial iront elevational view of .the illter shown in Figure 1; and

Figures 3, 4, 5 and 6 are reduced diagrammatic views similar to Figure 1, showing the entire iilter stack and illustrating the manner, of its operation. p

The structure used to illustrate the invention comprises an upright casing I, of more or less conventional design, and, therefore, provided with the customary air inletand outlet openings 2 and 3 in its front and rear walls respectively, and an-oil bath 4 in its bottom. Also conventionally illustrated are a series of air lter units 5, stacked one upon the other, to form a continuous air lter curtain across the front air inlet opening 2. Theside and top edges o! the stack, as a whole, frictionally engage the customary sealing strip 6 of the casing I, while the bottom of the stack is sealed by its contact with the oil bath. The lter units 5 are preferably but not necessarily o! the viscous impingement type. Both ends 'of each unit are provided with fore and aft pins or studs 1, which preferably are spaced at equal distances from each other and from the next adjacent guide pin of a contacting unit.

. The studs 1 at each end of the units in the stack extend into a g'uideway 8 on the adjacent side wall of the casing. The guideway on one side wall cooperates with an identically shaped .'guideway on the other side wall to prescribe the endless path` along which the umts ultimately travel. 'I'he shape of the. guideways 8, which are Aof channel form, is such as to prescribe an end` less path of trayel which extends from the upper front part of the casing downwardly through the iiltering or stack section into the oil bath, horizontally through a soaking section within the bath, upwardly out of the bath through a drainage section to the upper rear part of the -casing and thence laterally to the upper end of the ltering section, the lateral return sec- /tion preferably being inclined obliluely downward toward the iiltering section.

To support the units in stacked relation, mechanical means have heretofore been provided to engage and hold the bottom unitof the stack until actuated by some other mechanism to release the lowermost unit only to engage and hold the next unit as it moves downwardly into the bottom position. In accordance with the present invention, however, such means' is eliminated because the flat shape of the guideways' 8 in the soaking section permits them to sup-y port the bottom unit in a4 horizontal position underneath the stack, while the sharply curved shape of the guideways'at the point of connection between filtering and soaking sections causes them to turn a downwardly moving unit from a vertical ltering position quickly to the horizontal soaking and stack supporting position. As a result, the stack is supported on the soaking unit and remains in a xed ltering position until such unit is removed, whereupon the weight of the stack becomes eiective to force the lowermost ltering unit into the soaking section, during which it is forced yto assume the horizontal stack supporting position vacated by the removed mit. y

To prevent the suddendroppingl of the stack, when a bottom unit is removed, the air outlet face oi' each unit 5 may -be provided at one edge, the lower edge when such unit is in the stack, with an outwardly projecting cam 9 prei senting a, rounded or cam face which ultimately engages the adjacent and preferably rounded edge of the bottom unit of the stack as the latter is pulled from its stack supporting position.

Heretofore, eitherra p'air of endless chain conveyors operating at diierent speeds, or a single endless chain conveyor having special gears to alter its shape and path, hasbeen provided to remove the bottom (horizontal) unit from the stack and convey it to the top of the stack. The present-,invention makes possible the use of a single and simply shaped conveyor in place of such special conveyors. A straight-.sided conveyor, for example, composed of a pair of vertically arranged laterally spaced endless sprocket chains I may beA used. 'Ihese chains are positioned within the housing preferably with their up sides adjacent the air outlet opening 3 in operative position relatively to the up side of theA shown, a mechanical drive is provided, comprising a motor (not shown) suitably connected to one end of the upper shaft I2a'. Any desired type of control mechanism may be provided to regulate or vary the operation of the motor.

The conveyor chains III, which travel in the clockwise direction indicated by arrow T, each carry, at corresponding points along their length, apair of closely associated fore and aft fingers I3 and I4. links of each chain to lie closely together along the straight portions of chain travel and move angulariy apart along the curved portions thereof. They operate to engage the studs 1 of the filter units and to move them in the manner hereinafter described.

While the filter may be operated continuously or intermittently in any desired manner, its intermittent operation not only is preferred but preferably instituted when the parts are positioned as shown in Figure 3 and then continued through one complete uninterrupted cycle of operation which returns the ngers I3 and I 4 to their Figure 3 position. With reference to Figure 3, then, it will be noted that the stack, composed of units C to 5G inclusive, is supported. upon `a horizontal unit 5B in the soaking section, while an additional unit iA'is vertically arranged in the drainage section. This unit is protected from the air flow by a shield Il secured to the casing I. While the drainageunit 5A may be supported in drainage position in any suitable manner, it can be conveniently supported by the forefingers I3 of the conveyor chains III. y

After it has been supported in such position for a suitable drainage period, the control operates automatically to set the conveyor in motion. The conveyor slowly carries unit 5A upwardly to the return section of the guideways 8. As the unit 5A moves into the inclined return section, it passes away from the conveyor and thus becomes disengaged from -the iingers, ultimately reaching the top of the stack as shown in Figure 4.

The conveyor, however, continues to move downwardly, carrying the fingers Il and I 4 into the oil bath as shown in Figure 5. As the flnthe stack no'w becomes eil'ective to institute the downward-movement oi' the lowermost Avertical unit 5C from -the filtering section .toward the soaking section. In so doing, the unit 5C presses against the soaking unit 5B tending i90 1li These fingers are secured to separate forward, but such-forward thrusting movement of the soaking unit is prevented by the aft fingers I4 of the conveyor. At the same time, the conveyor operates through the aft finger Il .to controland restrain the gravitational movement of the stack as a whole.

As the conveyor continues to move the unit 5B l 'soon as unit 5C reaches the `soaking position, its

movement will cease, but the conveyor continues to move the unit 5B until it emerges completely from the oil bath and reaches the drainageposition shown in Figure 6. 'I'his completesthe cycle of operation; consequently, the conveyor is stopped until the next unit 5B completes i-ts drainage whereupon the next cycle of operation may be instituted.

Although the aft finger Il, with or without the aid of cam 9 on the lter units, will ordinarily control the gravitational movement of the stack in a satisfactory manner, it may be desirable, in vsome cases. to secure greater uniformity in the rate at which the stack is lowered. For

this reason additional stack` restraining means are illustrated in the drawings. Such means includes a star or sprocket i6 mounted upon a hub I'I, which is keyed to a `rotatable shaft I8.' the latter shaft being connected by. sprocket."

chain I9 to a smaller sprocket 20 on lowerlconveyorshaft IIa. 'Ihe position of stari I8 is such .that its teeth successively extend intd the space between successive studs of the stack. filter units as the stack is lowered. The star I6 is connected to hub I1 through a clutch which permits the star to remain stationary while the stack is sta-,

in the shallow section of the slot and to release them in the deep section thereof.

The star I8 is thus adapted to remain stationary while the conveyor moves orto rotate as the conveyor moves, but is eifectively prevented by the clutch from rotating at a speed greater than the rotational speed ofthe lower conveyor shatt IIa. As a result when the stack is supported by a unit in the soaking position, the star I6 is unable to rotate due to its engagement with the studs of units in the stationary stack hence,

it remainsrstationary even though the conveyor may be moving. However, when the conveyor,- in moving. Pulls the soaking unit from its stack supporting position, the resulting sudden downward movement of 'the stack will tend to rotate the star I6 rapidly, at a rate faster than that of .the

hub I'I upon which the star is mounted. 'I'he initial movement of the star, however, rolls the ball 22 toward the shallow end of 'the tapered slot 2| and thus effectively secures the star to the hub. 'I'his necessarily compels the star to rotate with the hub Il'and'limits the further lowering movement of the stack accordingly.

- While the advantages of this structure will be readily appreciated, it may be noted that:I the offset of the stack from the down side of the conveyor makes possible the employment of a straight sided conveyor with resuitingsimpliilca- $19!? 91 structure; the laterally inclined top guidel'lo inits rear end portion extends underneath the stack to support the same while its front end bridges the offset between the, stack and the conveyor sufiicently to enablie the latter to engage and remove the soaking unit. A particular feature of the -invention is that it permits the use of the conveyor or other means for supporting a unit in the drainage position while another unit remains in the oil bath where it becomes thoroughly soaked and thus thoroughly cleaned of its dirt content. The arrangement-of the soaking unit in stack supporting position is also highly advantageous, since it removal automatically causes the'stack to be lowered and another unit to assume the stack supporting soaking position. The use of an extra finger on the conveyor provides a satisfactory means for controlling the downward movement of the stack, while the -additional stack restraining means insures an eiective way of lowering the stack in a slow or gradual manner. Structures of this character have the further advantage of always presenting the same face of the filtering units to the air flow; hence, the units not only may be progressively packed but may be replaced or repacked from time to time to provide the same or different ltering density.

Having described my invention, I claim: y

l 1. An air lter comprising: a casing having an air passageway; a lter unit horizontally arranged in the lower part of said casing; a stationary frame for supporting said unit; a stack of movable lter units vertically arranged one over the other across the passageway, said stack resting upon said horizontally arranged unit; means for removing the horizontal unit horizontally from underneath the stack and transferring it to the top of said stack; the weight of said stack causing it to move gravitationally downward upon the removal of said horizontal unit; and means for turning the downwardly moving lowermost vertical unit of the stack into the stack supporting horizontal position vacated by the removed unit. V 2. An air lter of the character having a flat bottomed endless vertical path of unit travel.

comprising: a lter unit horizontally arranged along the flat bottom of said path; stationary guideway means to support said unit; a stack of filter units vertically arranged one over the other along the down side of said path, said stack resting upon said horizontal unit; and means for removing the horizontal unit in a horizontal direction from underneath the stack and conveying it along said endless path to the top ofthe stack; said stack moving downward upon the removal of said horizontal unit; said guideway means frictionally engaging the lowermost vertical unit of the downwardly moving stack to turn such unit to thehorizontal stack supporting position while it remains in contact with the succeeding vertical unit of the stack.

3. An air lter comprising: a casing having a bottom oil bath and an air passageway above said bath; a iilter unit arranged to soak within said bath; a stationary frame for supporting said soaking unit; a stack of lter units ver.-`

-unit horizontally lfromV underneath the stack and j transfer it to the top of the stack; said stack moving downward upon the removal of. said soaking unit; means for 'guiding the downwardly moving lowermost vertical unit of the stack into the stack supporting soaking position vacated by the preceding soaking unit; and means for moving the conveyor.

4. An air iilter comprising: a casing having a bottom oil bath and an air passageway above said bath; a iilter unit arranged to soak within said bath; means for supporting said soaking unit; a stack of lter units verticallyarranged one over the other in air ltering position across the passageway, said stack resting upon said soakingv unit; a unit-arranged in drainage position above said bath; means for supporting4 said draining unit; conveyor means operative, upon movement, to transfer the draining unit to the top of the stack. and the soaking unit to the drainage position; said stackpmoving downward upon the removal of said soaking unit; means for vguiding the downwardly Amoving lowermost vertical unit to the stacksupporting soaking position vacated by the precedingl soaking unit; and means for moving the conveyor.

bath; means for supporting said draining unit;

conveyor means operative, upon movement, to transfer the draining unit to the top of the stack and the soaking unit to the drainage position; said stack moving downward upon vthe removal of said soaking unit; means for turning the downwardly moving lowermost vertical unit of the stack horizontally into the stack supporting soaking position vacated by the preceding soaking unit; and means for moving the conveyor.

6. An air lter comprising: a casing having a bottom oil bath and an air flow passageway above said bath; guideway means prescribing an endless path of unit travel which extends from a top return section downwardly .through a ltring section into the oil bath, horizontally through a soaking section within the bath' and thence upwardly out of the bath through'a drainage section to the top return section; a filter` unit horizontally supported in the soaking section by the guideway means; a stack of filter units vertically arranged one 'over the other in the ltering section, said stack resting upon the soaking unit; afilter unit vertically arranged in the drainage section; a conveyor supporting the drainage unit in the drainage section, said conveyor being operative when moved to convey the drainage unit to and release it at the ton return section and to convey the soaking unit -to and support it in the drainage section; and means for so moving the conveyor; said stack being arranged for wherein a iorenger is mounted on an endless conveyor for movement along a vertically arranged endless path, having straight and curved portions, during which it enters the space between fore and aft end studs of a lter unit at theA fore end of a stack-forming series, which is mounted for vertical movement across an air duct, to remove such unit. convey it to and release it at the aft end thereof, comprising: an aft finger mounted on the conveyor adjacent the forenger, the fore and aft fingers being arranged to lie closely together along the straight portions of conveyor travel, to spread angularly apart alongthe curved portions thereof, to enter the stud space before they are fully spread apart and substantially to bridge the stud space when fully spread.

8. An air filter comprising: means forming a fixed guideway having a vertical section, the lower end of which curves abruptly into a flat.

bottomed horizontal section; a stack of lter units extending upwardly along said vertical section, said 'stack including a horizontally arranged unit resting o'n said horizontal section and a series of vertically arranged superposed units resting one upon the other withthe lowermost vertical unit resting upon the horizontal unit due to the abruptness of the lower end curvature of said vertical section; and conveyor means for intermittently removing a unit at the lower end of the stack and replacing it at the other end thereof.

9. The air fllter`of claim 8, wherein: said conveyor means removes the bottom unit horizontally from underneath the stack; the units of the stack move gravitationally downward upon the removal of said horizontal unit; and said g'uideway means operates to turn the downwardly-moving lowermost vertical unit of the stack horizontally into the stack-supporting horizontal position vacated by the removed unit.

l0. An air filter comprising: a frame; a horizontally arranged bottom illter unit removably asada@v supported on said frame a stack of movable lter units vertically arranged one over the other, said stack resting upon theatt upper-face portion'of said bottom unit; a straight-sided conveyor, having symmetrically curved end portions, vertically arranged with its lower end adjacent the fore end of said bottom unit and Withits downside oiset from the vertical units of `said stack;

to, and release it at, the top of the stack; means for moving the conveyor; the units of said stack moving gravitationally downward upon the removal of said bottom unit; and means for turning the downwardly moving lowermost vertical unit of the stack into the stack-supporting horizontal position vacated by the preceding removed bottom unit. l

1l. An air lter comprising: a frame; a vertical stack of filter units supported in air ltering position through the engagement of its bottom unit with 'said frame; a conveyor mechanism for intermittently removing the bottom unit of the stack and replacing it at the top thereof; the weight of the stack being effective, upon the removal of each bottom unit, to cause the succeeding lowermost unit of -the stack to move gravitationally downward into the stack-supporting position vacated by the preceding bottom unit; a rotatable member mechanically connected to and driven by the stack during the lowering movement thereof; and clutch means interposed between said conveyor and rotatable member to control the rate of the lowering movement of the stack, said clutch means being operative to connect said member to said conveyor when a bottom unit is removed from the stack-support- .ing position, and to disconnect said parts when said bottom unit is replaced by the succeeding unit of the stack. 1

ARTI-HTR. NU'I'IING.

said conveyor being operative, when' `moved, to engage said bottom unit, transferfit 

